Light olefins, such as ethylene, serve as feeds for the production of numerous chemicals. Olefins traditionally are produced by petroleum cracking. Because of the limited supply and/or the high cost of petroleum sources, the cost of producing olefins from petroleum sources has increased steadily.
Alternative feedstocks for the production of light olefins are oxygenates, such as alcohols, particularly methanol, dimethyl ether, and ethanol. Alcohols may be produced by fermentation, or from synthesis gas derived from natural gas, petroleum liquids, carbonaceous materials, including coal, recycled plastics, municipal wastes, or any organic material. Because of the wide variety of sources, alcohol, alcohol derivatives, and other oxygenates have promise as an economical, non-petroleum source for olefin production.
Small pore molecular sieve catalysts, such as SAPO-34, are quite successful in converting methanol and dimethyl ether to olefins. However, methods are always needed for improving the performance of such small pore molecular sieve catalysts.
Some have suggested using low surface area supports (hereinafter "monolithic supports") containing zeolite catalysts. The use of a monolithic support could produce a relatively low pressure drop at low residence times and facilitate more uniform temperature distribution in the catalyst bed. However, zeolites are relatively hydrophilic and certain molecular sieves, particularly silicoaluminophosphate (SAPO) molecular sieves, are relatively hydrophobic. Materials that might be effective to bind a relatively hydrophilic zeolite catalyst to a monolithic support would not necessarily be effective to bind a relatively hydrophobic non-zeolitic catalyst to a monolithic support.